LEWISTON ? Home prices are on the rise in this region as new residential developments spring up as part of an upscale housing boom.

Long regarded as blue-collar communities, Lewiston and Auburn are seeing a surge in single-family homes and condominiums that are fetching prices that were once reserved for the pricier southern and coastal areas of Maine.

A five-lot subdivision on the outskirts of Lewiston has homes that are selling for $325,000 and more. In Auburn, new homes at Vista Heights are commanding $369,000 and more, while condominiums on the former Mid-State College site are getting $259,000 for starters.

A developer is now planning 30 condominiums in the former Cowan Mill in Lewiston, with prices ranging from $275,000 to $525,000.

Real estate professionals say several factors ? a growing class of executives at area companies, continued low interest rates and shifting demographics ? are coming together to create demand for upscale housing.

But the single biggest factor is that Portland’s high prices are sending home buyers 30 miles up the Maine Turnpike to where they can get a lot more home for the buck.

Sharon Millett, president of Millett Realty-Coldwell Banker, said she first saw people from Portland inquiring about homes in the Lewiston-Auburn area about five years ago, but the interest is now growing fast.

“People are priced out of the southern Maine market,” said Millett, who’s been selling real estate locally for 35 years. “The 25-minute commute isn’t such a bad thing when you compare what you get for the money.”

The median home price in Androscoggin County stood at $152,000 in March, according to the Maine Real Estate Information System. That compared with $239,900 in Cumberland County.

But the prices in Androscoggin County had risen 21.6 percent in the past year as of March, or nearly double the 12.1 percent rise in Cumberland County.

While many buyers are coming from the south, there also is a growing number of local buyers.

Greg Mitchell, Lewiston’s assistant city administrator, said when Central Maine Medical Center’s heart center opened two years ago, there was a lack of executive-class housing stock.